Luke Popovich, a spokesman for the National Mining Association, said the IARC decision has "little bearing" on current conditions. Popovich said the recent studies aren't relevant, because they looked at worker exposures from the 1950s until the 1990s, when older and dirtier equipment was in use.

"It therefore does not reflect the technology changes that have been made since then," he said.

Industry groups and clean-air advocates alike say recent improvements are dramatic. The Diesel Technology Forum and the National Resources Defense Council both estimate that diesel emissions, including dangerous particles, are reduced by 99% in newer engines.

It would be easier to list the things you breathe in on a daily basis that aren't carcinogenic than to list the things that are. You could live in an environment free of pollutants and still develop cancer because it is a mutation in the DNA of a cell... It's not like a bar of cigarette tar in your lungs becomes cancer cells, it increases the probability that a lung tissue cell in close proximity to it will intake molecules of tar and cause the DNA to mutate and make a cancer cell.
Now I'm saying go stick your face in your buddy's Duramax tailpipe or anything... but I wouldn't worry about it just driving through traffic than I would the pesticides they put on your fruit